Do you have the items you want to sync to the watch in a Collection that is set to sync with the watch? In the Explore app, if you go to Devices > Select your Quatix > Sync Settings , if you have it set to "Sync Everything," you may want to try switching it to "Sync Selection" then set your Primary collection. Then, add the items you want to sync to the watch to the Primary collection and sync the watch from the Devices page.
This article has info about setting the Primary Collection: Setting a Primary Collection with the Garmin Explore Website or App
This article is for handheld GPS devices, but most of the troubleshooting steps would apply for your watch if it still isn't working by setting a Primary Collection: My Garmin Handheld is Not Syncing or Staying Connected to the Garmin Explore App
If it still isn't working, please contact Product Support so we can assist you with this.